The electrical connection between different electrical devices may be implemented in various ways. Independent from the actual implementation, a reliable electrical connection is desired throughout the lifetime of the device. For example, package in package integration and integration of passive components into packages using Cu-redistribution layers like FO-WLB (fan-out wafer level ball grid array package) and FO-Panel (fan-out panel) technologies use a direct contacting of solder pads or solder balls via sputtered or plated Cu contacts or lines. Reliability problems can occur at the contact area because the diffusion barrier liner on top of the Sn surface tends to be leaky. Sn and Cu diffusion processes can appear during high temperature storage or operation temperature and can lead to voids at the contact interface and finally to contact opens during lifetime. An improvement of the reliability of inter-connects may be desired.